Search results for "CONSTRAINTS"
showing 10 items of 149 documents
The Large Observatory for X-ray Timing (LOFT)
2012
High-time-resolution X-ray observations of compact objects provide direct access to strong-field gravity, to the equation of state of ultra-dense matter and to black hole masses and spins. A 10 m^2-class instrument in combination with good spectral resolution is required to exploit the relevant diagnostics and answer two of the fundamental questions of the European Space Agency (ESA) Cosmic Vision Theme "Matter under extreme conditions", namely: does matter orbiting close to the event horizon follow the predictions of general relativity? What is the equation of state of matter in neutron stars? The Large Observatory For X-ray Timing (LOFT), selected by ESA as one of the four Cosmic Vision M…
FISH: Face Intensity-Shape Histogram representation for automatic face splicing detection
2019
Abstract Tampered images spread nowadays over any visual media influencing our judgement in many aspects of our life. This is particularly critical for face splicing manipulations, where recognizable identities are put out of context. To contrast these activities on a large scale, automatic detectors are required. In this paper, we present a novel method for automatic face splicing detection, based on computer vision, that exploits inconsistencies in the lighting environment estimated from different faces in the scene. Differently from previous approaches, we do not rely on an ideal mathematical model of the lighting environment. Instead, our solution, built upon the concept of histogram-ba…
Adding Path-Functional Dependencies to the Guarded Two-Variable Fragment with Counting
2017
The satisfiability and finite satisfiability problems for the two-variable guarded fragment of first-order logic with counting quantifiers, a database, and path-functional dependencies are both ExpTime-complete.
REDUCTION OF CONSTRAINT SYSTEMS
1993
Geometric modeling by constraints leads to large systems of algebraic equations. This paper studies bipartite graphs underlaid by systems of equations. It shows how these graphs make possible to polynomially decompose these systems into well constrained, over-, and underconstrained subsystems. This paper also gives an efficient method to decompose well constrained systems into irreducible ones. These decompositions greatly speed up the resolution in case of reducible systems. They also allow debugging systems of constraints.
Exports of Spanish manufacturing firms and financial constraints
2020
We investigate the role of financial constraints on firms’ exporting behavior, including firms’ export decision, export intensity, firms starting to export decision, and exports persistence. Our financial constraints variable is a synthetic variable that summarizes information on different dimensions such as total assets, profitability, liquidity, solvency, repaying ability, and (new in this type of analyses) the cost of external financing. Using data on Spanish manufacturing for the period 1992–2014, we find evidence supporting that financial health is relevant to explain small and medium-sized enterprises (SMEs) exporting decisions and starting to export decisions but not those of large …
Homeward Bound FDI: Are Migrants a Bridge over Trouble Finance?
2016
Migrants can lower cross-border investment barriers, help investors by providing information about their homeland and reduce transaction costs by sharing expertise on regulations, customs and procedures. In addition to generating these well-known networking effects, migrants can also provide valuable information about local finance, thereby easing the credit constraints foreign investors faced during the 2007 financial crisis. This paper sheds new light on the underlying mechanisms through which migration may affect foreign investment in the migrant's homeland by distinguishing between the effects on FDI's intensive and extensive margins. Gravity estimates for 140 countries for the period 2…
Robotic assistance for industrial sanding with a smooth approach to the surface and boundary constraints
2021
[EN] Surface treatment operations, such as sanding, deburring, finishing, grinding, polishing, etc. are progressively becoming more automated using robotic systems. However, previous research in this field used a completely automatic operation of the robot system or considered a low degree of human-robot interaction. Therefore, to overcome this issue, this work develops a truly synergistic cooperation between the human operator and the robot system to get the best from both. In particular, in the application developed in this work the human operator provides flexibility, guiding the tool of the robot system to treat arbitrary regions of the workpiece surface; while the robot system provides…
Holes in the Dike: the global savings glut, U.S. house prices and the long shadow of banking deregulation
2015
We explore empirically how capital inflows into the US and financial deregulation within the United States interacted in driving the run-up (and subsequent decline) in US housing prices over the period 1990-2010. To obtain an ex ante measure of financial liberalization, we focus on the history of interstate-banking deregulation during the 1980s, i.e. prior to the large net capital inflows into the US from China and other emerging economies. Our results suggest a long shadow of deregulation: in states that opened their banking markets to out-of-state banks earlier, house prices were more sensitive to capital inflows. We provide evidence that global imbalances were a major positive funding sh…
Dense matter with eXTP
2019
In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry (eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics o…
Testing for new physics with low-energy anti-neutrino sources: LAMA as a case study
1998
Some electroweak models with extended neutral currents, such as those based on the $E_6$ group, lead to an increase of the $\bar{\nu}-e$ scattering cross section at energies below 100 keV. We propose to search for the heavy Z' boson contribution in an experiment with a high-activity artificial neutrino source and with a large-mass detector. We present the case for the LAMA experiment with a large NaI(Tl) detector located at the Gran Sasso underground laboratory. The neutrino flux is known to within a one percent accuracy, in contrast to the reactor case and one can reach lower neutrino energies. Both features make our proposed experiment more sensitive to extended gauge models, such as the …